Imaging Lens and Imaging Apparatus Including the Same

Abstract

An imaging lens includes a first lens having a convex surface toward an object and positive refractive power, a second lens having positive or negative refractive power, a third lens having positive or negative refractive power, a fourth lens having a convex surface toward an image plane and positive refractive power, and a fifth lens having a concave surface toward an object and negative refractive power. The first through fifth lenses are arranged in order from an object to an image plane. The imaging lens satisfies the condition −0.2≦( Y−y p )/ y p ≦−0.05, wherein Y indicates an image height of a real chief ray, and y p indicates an image height of a paraxial chief ray.

What is claimed is: 
     
         1 . An imaging lens comprising:
 a first lens having a convex surface toward an object and positive refractive power;   a second lens having positive or negative refractive power;   a third lens having positive or negative refractive power;   a fourth lens having a convex surface toward an image plane and positive refractive power; and   a fifth lens having a concave surface toward an object and negative refractive power,   wherein the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in order from an object to an image plane,   wherein the imaging lens satisfies:
   −0.2≦( Y−y   p )/ y   p ≦−0.05,
 
 wherein Y indicates an image height of a real chief ray, and y p  indicates an image height of a paraxial chief ray. 
   
     
     
         2 . The imaging lens of  claim 1 , wherein the imaging lens satisfies:
   0.8<TL/f<1.5,   wherein TL indicates a distance along an optical axis between a vertex of an object side surface of the first lens to the image plane, and f indicates a focal length of the imaging lens.   
     
     
         3 . The imaging lens of  claim 1 , wherein the imaging lens satisfies:
   0.7< f/f 4<2.5,   wherein f indicates a focal length of the imaging lens, and f4 indicates a focal length of the fourth lens.   
     
     
         4 . The imaging lens of  claim 1 , wherein the imaging lens satisfies:
   1.0<| f/f 5|<4.0,   wherein f indicates a focal length of the imaging lens, and f5 indicates a focal length of the fifth lens.   
     
     
         5 . The imaging lens of  claim 1 , wherein the imaging lens satisfies:
   0.2< R 1/ f< 1.0,   wherein R1 indicates a radius of curvature of the object side surface of the first lens, and f indicates a focal length of the imaging lens.   
     
     
         6 . The imaging lens of  claim 1 , wherein the imaging lens satisfies:
     f/EPD≦ 2.5,   wherein f indicates a focal length of the imaging lens, and EPD indicates a diameter of an entrance pupil of the imaging lens.   
     
     
         7 . The imaging lens of  claim 1 , wherein one of the second and third lenses has positive refractive power and the other of the second and third lenses has negative refractive power. 
     
     
         8 . The imaging lens of  claim 7 , wherein the imaging lens satisfies:
   1.6≦N 1-4 ≦2.2, and
     15≦V 1-4 ≦29,
   wherein N 1-4  and V 1-4  respectively are a refractive index and an Abbe number of a lens having negative refractive power from among the second lens and the third lens.   
     
     
         9 . The imaging lens of  claim 1 , wherein the imaging lens satisfies:
   1.51<N 5 <1.56,   wherein N 5  indicates a refractive index of the fifth lens.   
     
     
         10 . The imaging lens of  claim 1 , wherein each of the first to fifth lenses has at least one aspheric surface. 
     
     
         11 . The imaging lens of  claim 1 , wherein an image side surface of the fifth lens is an aspheric surface without an inflection point. 
     
     
         12 . An imaging lens comprising:
 a first lens having a convex surface toward an object and positive refractive power;   a second lens having positive or negative refractive power;   a third lens having positive or negative refractive power;   a fourth lens having a convex surface toward an image plane and positive refractive power; and   a fifth lens having a concave surface toward an object and negative refractive power,   wherein the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in order from an object to an image plane,   wherein the imaging lens satisfies:
   30°≦CRA max ≦45°, and
 
   0.5<TL/(2* y   p )<0.75, 
 wherein CRA max  indicates a maximum value of a chief ray angle (CRA) incident to the image plane according to image heights, TL indicates a distance along an optical axis between a vertex of an object side surface of the first lens to the image plane, and y p  indicates an image height of a paraxial chief ray. 
   
     
     
         13 . The imaging lens of  claim 12 , wherein the imaging lens satisfies:
   −20≦(((1/ f )*( Y/tan θ )−1))*100≦−5,
   wherein f indicates a focal length of the imaging lens, Y indicates an image height of a real chief ray, and θ indicates a half field of view.   
     
     
         14 . The imaging lens of  claim 12 , wherein the imaging lens satisfies:
   −1.6<( R   9   +R   10 )/( R   9   −R   10 )<−0.7,
   wherein R 9  indicates a radius of curvature of an object side surface of the fifth lens, and R 10  indicates a radius of curvature of an image side surface of the fifth lens.   
     
     
         15 . The imaging lens of  claim 12 , wherein one of the second and third lenses has positive refractive power and the other of the second and third lenses has negative refractive power. 
     
     
         16 . The imaging lens of  claim 12 , wherein the imaging lens satisfies:
   1.6≦N 1-4 ≦2.2, and
     15≦V 1-4 ≦29,
   wherein N 1-4  and V 1-4  respectively are a refractive index and an Abbe number of a lens having negative refractive power from among the second lens and the third lens.   
     
     
         17 . The imaging lens of  claim 12 , wherein each of the first to fifth lenses has at least one aspheric surface. 
     
     
         18 . The imaging lens of  claim 14 , wherein the image side surface of the fifth lens is an aspheric surface without an inflection point. 
     
     
         19 . An imaging apparatus comprising:
 an imaging lens comprising:
 a first lens having a convex surface toward an object and positive refractive power; 
 a second lens having positive or negative refractive power; 
 a third lens having positive or negative refractive power; 
 a fourth lens having a convex surface toward an image plane and positive refractive power; and 
 a fifth lens having a concave surface toward an object and negative refractive power, 
 wherein the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in order from an object to an image plane, 
 wherein the imaging lens satisfies:
   −0.2≦( Y−y   p )/ y   p ≦−0.05,
 
 wherein Y indicates an image height of a real chief ray, and y p  indicates an image height of a paraxial chief ray; and 
 
   an image sensor configured to convert an optical image formed by the imaging lens into an electric signal.   
     
     
         20 . The imaging apparatus of  claim 19 , further comprising a body having a body thickness of 7 mm or less, and the imaging lens is arranged such that an optical axis direction of the imaging lens corresponds to a direction of the body thickness.